Interpolymers of alkylidene esters of alpha-methylene monocarboxylic acids with vinyl and vinylidene compounds



Patented Feb. 8, 1944 2,341,334 INTERPOLYMERS F ALKYLIDENE ESTEBS W MONOOABBOX- YLIC AOHISWITHVMLWVMHDENE oomrouuns Henry John Richter, Wilmington. DeL, assignmto E. I. du Pont de Nemours & Company, Wilmington, DeL, a corporation of Delaware No Drawing. Application August 21, 1941, Serial No. 401.143

2 Claims.

This invention relates to synthetic resins, and, more particularly. to vinyl type polymers. and. still more particularly, to interpolvmers of alkylidene esters of alpha-methylene monocarboxylic acids with other polymerizable materials.

This application is a continuation-in-part of applicant's copending application Serial No. 261,767. filed March 14, 1939, now Patent No. 2,312,193.

This invention has as an object the production of new synthetic materials. Another object is the production of new synthetic resins. A further obiect is to provide synthetic resins of variable hardness and water permeability by .interpolymerization of alkylidene esters of alphamethylene monocarboxylic acids with other polymerizable materials. Other objects will become more apparent hereinafter.

These objects have been accomplished by interpolymerizing alkylidene derivatives of alphamethylene monocarboxylic acids with a polymerizable unsaturated organic compound containing a methylene group attached by an ethylenic double bond (CH:=) to a carbon atom which is. in turn, attached to at least one negative group. I i

The alkylidene derivatives or alpha-methylene monocarboxylic acids may be conveniently preby reacting aldehydes with anhydrides of alpha-methylene monocarboxylic acids in the presence oi a: catalyst, as is disclosed and claimed in applicant's copendins application referred to above. By way of illustration, the following two examples show how this reaction can be carried out.

Exams: A

Preparation of ethullde'ne dimethacrulate from acetaldehude and methacn/lic uflhfldride Anhydrous ferric chloride (0.5 g.) was dissolved in 46 g. of cold methacrylic anhydride in a reaction vessel. Acetaldehyde (13.2 g.) ww added in portions with stirring and cooling at such a rate that the temperature did not exceed 18 C. after each addition. The mixture was cooled to 5 C. beiore the next portion was added. After completion of the addition, the vessel was closed. placed in an ice bath. and eventually allowed to come slowly to room temperature. After standing a total of about 6 hours, the product was diluted with ether and washed first with cold water and then with cold dilute aqueous sodium .cold dilute sodium hydroxide prior to polymerization. By this method, a 67 per cent yield of so with cold dilute sodium ethylidene dimethacrylate was obtained.

Exmu B Preparation of. methylene dimethccrillate from paraiormaldehude and metnccrulic cnhrdride Ten (10) drops 01' concentrated sulfuric. acid were slowly added to a mixture composed of 6 g. paraiormaldehyde, 31 g. methacrylic anhydride and 1 g. cuprous chloride in a reaction vessel. This mixture was then heated in an oil bath at 100 C. for 20 minutes and then for about 5 minutes at 130 C. After cooling and diluting with ether, the mixture was washed well with cold dilute aqueous sodium carbonate solution iollowed by washing with water, and then was dried over anhydrous magnesium sulfate. Hydroquinone was added. the ether removed. and the residue distilled under reduced pressure collectin the fraction boiling at 93-95" 0.]9-10 mm. The yield was 25 g. The distilled product washed hydroxide solution prior to polymerization.

As will be seen from the above examples, the reaction is carried out in the presence of a condensation catalyst. such, for example. as sulfuric 36 acid or ferric chloride. The esters thus formed readily polymerize to yield high-melting, waterinsoluble polymers. The esters interpolymerize very readily with negatively substituted vinyl and vinylidene compounds to give inter-polymers hav- 40 log desirable characteristics.

In order that the invention may be more fully understood. the following specific examples are given. Such examples are merely by way or illustration, and the invention is not limited thereto as will become more apparent hereinafter.

EXAMPLE I Interpolumerization of ethulidene dimethacrfllate and methyl methacrvlcte A mixture comprising grams of monomeric methyl methacrylate and 10 grams pi ethylidene dimethacrylate was allowed to remain at 60 C. for 1 /2 days after which time it had polymerized to a clear, insoluble. and water-resistant polymer which softened at 143 C. as compared with an unmodified methyl methacrylate polymer which softened at 122 C.

Interpolymers containing 2, 5, and 20 per cent of ethylidene dlmethacrylate were prepared by a similar procedure. These polymers were clear, hard, and insoluble and softened at 123 (3., 127 C., and 183 C. respectively.

EXAMPLE II Inierpolymerization of vinyl acetate and ethylidene dimethacrylate A mixture comprising 22.5 g. monomeric vinyl acetate. 2.5 g. ethylidene dimethacrylate. and 0.2 g. benzoyl peroxide was allowed to remain at 60 C. for 2 hours during whichperiod it polymerlzed to give a spongy polymer which, when molded at 50-100 C. and 1000-3000 pounds pressure. gave a product which was clear, tough, and flexible.

Exsnnn II[ Interpolymerization of methyl methacrylate and methylene dimethacrylate Forty-seven and five-tenths (47.5) grams of monomeric methyl methacrylate and 2.5 grams of methylene dimethacrylate were interpolymerized by heating for 16 hours at 60 C. A clear insoluble casting, formed from the interpolymer, softened at 120 C. and was not affected by boiling water.

EXAMPL: IV

Interpolymenzation of methyl acrylate and ethylidene dimethacrylate A mixture of 11.25 grams of methyl acrylate, 1.25 grams of ethylidene dimethacrylate, and 0.1 gram of benzoyl peroxide was polymerized by heating for 8 hours at 60 C The resulting interpolymer was clear, tough, and insoluble in toluene.

EXAMPLE V Interpolymerization of methyl methacrylate and butylidene dimethacrylote A mixture comprising 11.25 grams of methyl methacrylate and 1.25 grams of butylidene dimethacrylate was polymerized by heating for 1 day at 60 C. The resulting interpolymer was clear, hard, and insoluble and softened at 120 C.

EXAMPLE VI Interpolymerization of styrene and ethylidene dimethacrylute A mixture of 22.5 grams of styrene, 2.5 grams of ethylidene dimethacrylate, and 0.1 gram of benzoyl peroxide was polymerized by heating for 18 hours at 60 C. The resulting interpolymer is clear, tough, and insoluble in toluene.

Exnlru VII Interpolymerization of methyl methacrylate, tetmmethallyl silicate, and ethillidene dimethacrylate A mixture comprising 17.5 grams of methyl methacrylate, grams of ethylidene dimethacrylate, and 2.5 grams of tetramethallyl silicate was polymerized by heating for 16 hours at 60 C.

The resulting interpolymer was hard and insoluble in toluene.

In its broadest conception, this invention relates to interpolymers 0i alkylidene esters of alpha-methylene monocarboxylic acids, The monomers are made by condensation of aldehydes with acid anhydrides. The aldehydes may contain alkyl, aryl, aralkyl, or alkenyl groups, such, for example, as acetaldehyde. butyraldehyde, valeric aldehyde, heptaldehyde, benzaldehyde. o-toluyl aldehyde, phenylacetaldehyde, cinnamic aldehyde, acrolein, crotonaldehyde, and the like. The preferred aldehydes are formaldehyde and those containing saturated allwl radicals, and especially preferred are acetaldehyde and formaldehyde (or para-formaldehyde).

The acid anhydrides with which the aldehydes are reacted are anhydrides of monocarboxylic acids having an alpha-methylene group. The anhydride may be derived from an acid containing alkyl, aryl, or halogen groups, such, for example, as alpha-methacrylic acid anhydride, alpha-butyl acrylic acid anhydride, alpha-phenyl acrylic acid anhydride. alpha-chloro-acrylic acid anhydride and the like. The preferred acid anhydrides are acrylic acid anhydride and methacrylic acid anhydride. the latter being especially preferred.

Among the aikylidene esters of alpha-methylene monocarboxylic acids made by condensation of aldehydes with acid anhydrides, the following are especialy suitable for the present invention; e. g., methylene diacrylate, methylene dimethacrylate, methylene di(alpha-butylacrylate), methylene di(alpha-phenylacrylate), methylene di(alpha-chloroacrylate), ethylidene diacrylate, ethylidene dimethacrylate, ethylidene di(alphabutylacrylate), ethylidene di(alpha-phenylacrylate), ethylidene di(alpha-chloroacrylate), benzylidene diacrylate, benzylidene dimethacrylate. benzylidene di(alpha-butylacrylate) benzylidene dii alpha-phenylacrylate) benzylldene di (alphachloroacrylate), cinnamylidene diacrylate, cinnamylidene dimethacrylate, cinnamylidene di- (alpha-butylacrylate), cinnamylidene di(alphaphenylacrylate), cinnamylidene di(alpha-chloroacrylate). crotonylidene diacrylate, crotonylidene dimethacrylate. crotonylidene di(alpha-butylacrylate), crotonylidene di(alpha-phenylacrylate), and crotonylidene di(alpha-chloroacrylate) The condensation is carried out in the presence of a condensation catalyst. By way of example may be mentioned ferric chloride, zinc chloride. aluminum chloride, sulfuric acid, phosphoric acid, aromatic sulfonic acids, aliphatic sulfonic acids, and the like. The preferred catalysts are ferric chloride and concentrated sulfuric acid.

It was found that, in reacting para-formaldehyde with methacrylic anhydride in the presence of concentrated sulfuric acid, the addition of a small amount of cuprous chloride favorably influenced the size of yield, presumably due to an inhibiting action on the polymerization of the reacting materials. Accordingly. it is preferred that cuprous chloride or other suitable polymerization inhibitors be included in the reaction mixture when concentrated sulfuric acid is used as a catalyst. Cuprous chloride or other suitable polymerization inhibitors may also be used in conjunction with the other condensation catalysts. This is of particular advantage if the reaction is to be carried out at relatively high temperatures.

The esters formed as above described readily polymerize to clear, hard, water-insoluble, somewhat brittle polymers. This polymerization may be carried out in the presence or absence of polymerizatlon catalysts by heating the monomers at any temperature up to the decomposition point of the monomers or polymers and the polymerization may be effected at atmospheric, superatmospheric, or subatmospheric pressures. Solvents may be used, if desired, or the polymerization may also be carried out in aqueous emulsion in the presence of a suitable catalyst and emulsifying agent. Unmodified polymerized alkylidene dimethacrylates may be used wherever high temperature-softening and quite heat-stable resins are desired. It is possible to modify the properties of other polymeric materials desirably by interpolymerization of their monomers with the new unsaturated aikylidene derivatives. For example, the softenin temperature of polymeric vinyl compounds can be raised and their rate of polymerization accelerated by interpolymerization with these agents.

The alkylidene esters of alpha-methylene monocarboxylic acids may be used in combination with other polymerizable materials in the preparation of cast articles and molding powders. In the preparation of cast articles by bulk, poly merization of an alkylidene dimethacrylate with another polymerizable substance, the amount of alkylidene dimethacrylate may be varied widely depending on the results desired. The softening temperature of the interpoiymer of methyl methacrylate and ethylidene dimethacrylate or methylene dimethacrylate increases as the amount of th alkyiidene dimethacrylate is increased.

In general, it has been found advantageous to interpolymerlze the polymerizable materials of the present invention with a polymerizabie organic compound containing a methylene (CH2) group attached by an ethyienic double bond to a carbon atom, which is, in turn, attached to at least one negative group. Negative group," as here used, means an organic radical containing a carbon atom joined to a second atom by more than one bond, the muiti-bonded carbon atom being separated from the abovementioned ethylenic double-bonded carbon atom by not more than one atom. Among such vinyl and vinylidene compounds may be mentioned acrylic and methacrylic acids; esters of methacrylic acids such as methyl, ethyl, and butyl methacrylates: esters of acrylic acid such as methyl, propyl, and octyi acrylates; acrylic nitrile and methacrylic nitrile; vinyl acetate. isopropenyl acetate, vinyl formate, isopropenyl formate; methyl venyl ketone, methyl isopropenyl ketone, and phenyl vinyl ketone; butadiene and 2-methyl-1,3-butadiene; chloroprene and 2-chloro-3-methyi-l,3- butadiene; styrene and alphamethyl styrene. All of these compounds fall within that class of polymerizabie unsaturated organic compounds represented by the formula CHFC/ where X is hydrogen or alkyl and Y is an unand cin.-

wherein Z is alkyl.

These new unsaturated acid derivatives often increase the rate of polymerization 01' other polymerizable materials when they are interpolymerized with said other polymerizable materials. In a number of these cases, notably in the interpoiymerization of methyl methacrylate and ethylidene dimethacrylate, products are obtained which soften at higher temperatures than the unmodified polymeric methyl methacrylate. These products, in general, are not affected by boiling water.

The Polymeric aikylidene derivatives 01' alphamethylene monocarboxylic acid and the interpolymers formed by interpolymerizing these compounds with other polymerizable materials, either alone or in the presence of plasticizers, fillers, pigments. synthetic and natural waxes, are useful in the preparation of cast articles. Molded articles such as buttons, combs, containers, tubes, and the like can be prepared from the interpolymers described above. These polymers and interpolymers, either alone or in the presence of other resinous bodies, waxes, pigments, dyes, plasticizers, can be used in lacquers, paints, varnishes, and enamels for the coating of glass. metal, wood, and similar materials. They are also useful for coating and the impregnation of cloth, textiles, Wu and pap'fiand may be used in the preparation of reinforced collars, cuffs. and similar articles of clothing. The interpolymers are also useful in the making of optical elements such as lenses, prisms, etc.

Suitable changes may be made in the details of the process and any modifications or varialions which conform to the spirit of the invention are intended to be included within the scope of the claims.

I claim:

1. An interpolymer of methylene dimethacrylate and a polymerizable unsaturated organF: compound of the formula wherein X is a radical selected from the group consisting of hydrogen and alkyl and Y is an unsaturated radical selected from the group consisting of wherein Z is alkyl.

2. An interpolymer of methylene dimethacrylate and methyl methacrylate.

HENRY JOHN RICHTER. 

